Oxford Centre for Integrative Systems Biology, University of Oxford, Oxford OX1 3QU, United Kingdom.
Proc Natl Acad Sci U S A. 2012 Apr 24;109(17):6698-703. doi: 10.1073/pnas.1114000109. Epub 2012 Apr 10.
Recent data have shown that plasmid partitioning Par-like systems are used by some bacterial cells to control localization of protein complexes. Here we demonstrate that one of these homologs, PpfA, uses nonspecific chromosome binding to separate cytoplasmic clusters of chemotaxis proteins upon division. Using fluorescent microscopy and point mutations, we show dynamic chromosome binding and Walker-type ATPase activity are essential for cluster segregation. The N-terminal domain of a cytoplasmic chemoreceptor encoded next to ppfA is also required for segregation, probably functioning as a ParB analog to control PpfA ATPase activity. An orphan ParA involved in segregating protein clusters therefore uses a similar mechanism to plasmid-segregating ParA/B systems and requires a partner protein for function. Given the large number of genomes that encode orphan ParAs, this may be a common mechanism regulating segregation of proteins and protein complexes.
最近的数据表明，质粒分配 Par 样系统被一些细菌细胞用来控制蛋白复合物的定位。在这里，我们证明了这些同源物之一，PpfA，利用非特异性染色体结合在分裂时将趋化蛋白的细胞质簇分离。通过荧光显微镜和点突变，我们表明动态染色体结合和 Walker 型 ATP 酶活性对于簇分离是必不可少的。与 ppfA 相邻编码的细胞质感受体的 N 端结构域对于分离也是必需的，可能作为 ParB 类似物来控制 PpfA ATP 酶活性。因此，参与分离蛋白簇的孤儿 ParA 利用类似的机制与质粒分离 ParA/B 系统，并且需要伴侣蛋白来发挥功能。鉴于许多基因组编码孤儿 ParA，这可能是一种调节蛋白质和蛋白质复合物分离的常见机制。
